Cuscuta: A Parasitic Plant for Decoding Plant-to-Plant Communication

There are over 4,500 species of parasitic plants in the world, which is about 1% of all flowering plants. These plants are found in more than 20 plant families and are a significant part of terrestrial ecosystems globally. Among them, Cuscuta spp. (common name: dodder) is a rootless and leafless parasitic plant that can infect shoots (primarily stems) of herbaceous and woody plants. Interestingly, Cuscuta has served as a valuable model plant for the exploration of plant-plant interactions and molecular trafficking because molecules, including RNAs, DNAs, and proteins, are bidirectionally exchanged between host and Cuscuta. To understand the function of mobile molecules, we developed Agrobacterium-mediated Cuscuta transformation using 35S:RUBY. The stably transformed and regenerated RUBY C. campestris plants produced haustoria, the signature organ of parasitic plants, and these were functional in forming host attachments. Furthermore, the RUBY is not only a useful selectable marker for the Agrobacterium-mediated transformation, but also may provide insight into the movement of molecules from C. campestris to the host during parasitism. Thus this innovative approach opens new possibility for using parasitic plant to improve the insight of plant-plant interaction. By leveraging Cuscuta as a model system, we can gain unprecedented insights into the complex world of inter-plant communication and molecular exchange.